Interpretive Summary: Two of the major problems facing modern irrigation agriculture are a dwindling water supply and environmental pollution due to fertilizers, salts, and other agricultural chemicals. This paper reviews research done using subsurface drip irrigation which demonstrated increases in productivity (improved water use efficiency) through improved water and fertilizer management. Yields were increased in tomatoes, cotton, sweet corn, cantaloupes, and alfalfa without increases in applied water. The research also demonstrated significant reduction in deep percolation of applied water which reduced the transport of nitrate and salt to shallow ground water. This research demonstrated that subsurface drip irrigation has application in both field and perennial crops.

Technical Abstract:
Use of subsurface drip irrigation (SDI) has progressed from being a novelty employed by researchers to an accepted method of irrigation of both perennial and annual crops. This paper reviews the SDI research conducted by scientists at the Water Management Research Laboratory over a period of 15 years. Data are presented for irrigation and fertilization management on tomato, cotton, sweet corn, alfalfa, and cantaloupe for both plot and field applications. Results from these studies demonstrated significant yield and water use efficiency increases in all crops. Use of high frequency irrigation resulted in reduced deep percolation and increased use of water from shallow ground water when crops were grown in high water table areas. Uniformity studies demonstrated that after 9 years of operation SDI uniformity was as good as at the time of installation if management procedures were followed to prevent root intrusion.